Purifying alcohols



- The nature of the impurities Patented May 7, 1929. i

UNITED STATES PATENT ormca.

H'Y'YM E. BUG, 0F ROSELLE, NEW JERSEY, ASSIGNOB 1'0 STAI VDARD OIL DEVELOP- MENT COMPANY, A CORPORATION OF DELAWARE.

PURIFYING ALCOHOLS.

No Drawing.

This invention relates to the art of urifying water-soluble alcohols and wi fully understood from the following description.

lVhen alcohols are first produced, particularly by the process in which an unsaturated hydrocarbon, such as ethylene, propylene, and the like, is combined with sulfuric acid and the product hydrolyzed by means of water, they usually carry persistent odors foreign to the alcohol proper. varies and is not always known. In the case of secondary and tertiary alcohols produced from unsaturated compounds there are present besides olefines, ethers and higher alcohols, also sulfur compounds of unknown structure. Various chemical treatments for purification have been devised but such treatments are often apt to introduce other impurities by reaction with the alcohols or with the constituents carried by the alcohols.

In accordance with the present'invention, I )royide a purifying treatment which being o a. physical nature makes possible the production. of high grade alcohols, particularly from the point of view of odor, without damage to the alcohol molecules themselves. In most cases this treatment alone is sufficient but if desired a light chemical treatment may precede or follow.

I treat the alcohol as such, or after diluting with water as desired, with an organic liquid capable of taking up the undesired constituents. As such liquid, various sub stances may be used, keeping .in general the propertiesalso of ready separability from the alcohol, and such a degree of purity as will avoid any side contamination. Various 1 note of high boiling point, for example of initial boiling point above 500 F.

The treating liquid is thoroughly mixed and agitated with the alcohol-to be treated, and the mixture is then allowed to settle for stratification into layers and the treating liquid is drawn ofi'. Desirably this treatment is repeated with another charge of treating liquid; and by a plurality of such treatments in succession, the esired degree of purification may be efl'ected. The alcohol ls Application filed July 31, 18 23. Serial No. 854,981.

any other As an example illustrative of my process:

Crude isopropyl alcohol with about a volume of water, and a colorless odorless petroleum oil of about 570- 5 80 F., initial boiling point and having a viscosity of around 205-215 Saybolt at 100 F., are mixed in an agitator.device and are then settled to allow stratification into layers. The oil is removed and the alcohol is again agitated with another portion of oil. six to eight such washings are generally ficient. The alcohol is then rectified.

The relative amount of oil employed may vary within wide limits, but by using continuous agitators and suitable separators relativel small amounts are sufficient, and by intro ucing the fresh oil toward the end and cycling back used oil for the earlier treats, high elliciency may be realized. The oil which is fully loaded up may be subjected to steam distillation or refining treatments preferably diluted known in the petroleum industry and is then again fully available.

While I have referred more particularly to a highly refined white oillof petroleum character, it is to be understood that I contemplate using also various less highly refined petroleum oils, particularly those of the lubricating range, and even oils of still lower boiling points, keeping in view of course the desirability in any ticable separability between the alcohol to be treated and the hydrocarbons used to enable a ready separation. And while I have referred more es ecially to isopropyl alcohol by reason oi its predominant importance, it will be understood that other water-soluble alcohols can likewise be treated.

What I claim is:

1. In a process of purifyin an alcohol de rived from unsaturated hydrocarbons and an initial boilin point of about 570 to 580$ case of a sufliciently prac- F., separating the oil, repeating the treatment with ot r charges of a like oil a 111- rality of times, and distilling the alcoho 2. In a process of purifyin an alcohol derived from unsaturated hydrocarbons and capable of removal by stratlfication from admixture with petroleum oil, the improvement which comprises agitating the alcohol with a colorless petroleum oil having a boiling point above 500 F separating the oil, repeatin the treatment with other char es of a lilre oil a plurality of times, and istilling the alcohol.

3. In a process of purifying an alcohol derived from unsaturated hydrocarbons and capable of removal b stratification from admixture with petro eum oil, the improvement which comprises mixing the alcohol with a heavy petroleum oil, allowing the mixture to stratify, whereby two layers are formed containing respectively the bulk of the alcohol and the bulk of the oil, and separatin the layers.

4. hfethod according to claim 3, in which a colorless petroleum oil having an initial boiling oint of about 500 F. is used as the puri {ing agent.

5. n a process of purifyin an alcohol derived from unsaturated hy rocarbons and capabl of removal b stratification from admixture with petroleum oil, the'iinprovement which comprises treating the alcohol with refined petroleum hydrocarbons of boiling point above 500 F. and separating the hydrocarbons.

HYYM E. BUC. 

